1. Field of the Invention
The present invention relates to a biochemical processing apparatus, such as a deoxyribonucleic acid (DNA) testing apparatus, and to a container for the biochemical processing apparatus. In particular, the present invention relates to a configuration of a container for the amplification and purification of DNA samples and to an opening and closing mechanism for the container.
2. Description of the Related Art
For quickly and accurately analyzing the base sequence of a nucleic acid and detecting a target nucleic acid in nucleic acid samples, many methods based on hybridization reactions using a probe carrier, such as a DNA microarray, have been proposed. A DNA microarray is a collection of probes having a base sequence complementary to a target nucleic acid and attached to a solid surface, such as a bead or glass plate, at a high density. The detection of a target nucleic acid using the DNA microarray typically involves the following steps.
In the first step, the target nucleic acid is amplified by an amplification method, such as a polymerase chain reaction (PCR) method. Specifically, a first primer and a second primer are added to a nucleic acid sample, which is then subjected to temperature cycling in the presence of an enzyme. The first primer is specifically bound to part of the target nucleic acid, while the second primer is specifically bound to part of a nucleic acid complementary to the target nucleic acid. When a duplex nucleic acid containing the target nucleic acid is bound to the first and second primers, the duplex nucleic acid containing the target nucleic acid is amplified by an elongation reaction (hereinafter, this is referred to as “first PCR”).
After the duplex nucleic acid containing the target nucleic acid is sufficiently amplified, components, such as non-reacted primers and nucleic acid fragments, other than the amplified duplex nucleic acid are removed by purification. Examples of known purification methods include a method of attaching a duplex nucleic acid to magnetic particles and a method using a column filter.
After the purification, a third primer is added to the purified nucleic acid sample, which is then subjected to temperature cycling. The third primer is labeled with an enzyme, fluorescent material, light-emitting material, or the like and specifically bound to part of a nucleic acid complementary to the target nucleic acid. When the third primer is bound to the nucleic acid complementary to the target nucleic acid, a labeled target nucleic acid is amplified by an elongation reaction (hereinafter, this is referred to as “second PCR”).
As a result, if the target nucleic acid is contained in the nucleic acid sample, a labeled target nucleic acid is generated, while if the target nucleic acid is not contained in the nucleic acid sample, a labeled target nucleic acid is not generated.
In the second step, this nucleic acid sample is brought into contact with a DNA microarray so that a hybridization reaction between the nucleic acid sample and a probe on the DNA microarray takes place. If a target nucleic acid complementary to a probe is present, the probe and the target nucleic acid create a hybrid body.
The third step involves the detection of the target nucleic acid. The detection of whether a probe and a target nucleic acid have created a hybrid body can be made with a labeled material of the target nucleic acid. This allows a determination as to the presence of a specific base sequence.
Japanese Patent Laid-Open No. 7-107999 discloses an apparatus capable of independently and sequentially performing the multiple steps described above. This apparatus is configured such that a movable pipettor delivers necessary liquids to containers to allow reactions to take place.
A biochemical processing apparatus capable of performing a plurality of processing steps requires many spaces (containers) in which liquids are separately held. For example, such a biochemical processing apparatus requires containers which serve as holders for separately holding many reagents, and other containers which serve as reaction fields for performing biochemical processing.
A problem of contamination resulting from the transfer of liquid between such containers needs to be solved. Liquid often spatters, for example, when a pipetting device is used for the transfer of liquid. To solve this problem, it is preferable to configure the containers such that the transfer distance of liquid is reduced, that is, the containers are arranged in close proximity to each other.
This configuration is advantageous in that an area to be temperature-controlled is reduced, and that the size of a transfer device is reduced.
However, as the containers become closer to each other, the problem of contamination of reagents in adjacent containers grows.
There is another possible configuration in which the openings of the containers are covered with a film until immediately before use, and are opened as needed. However, the removal of the film causes liquid to evaporate during processing, such as PCR processing, which involves heating. Another problem is condensation which may occur during processing that involves cooling.